Gear changing mechanism



y 21, 1940- Y. SEKELLA GEAR CHANGING MECHANISM 2 Sheets-Sheet 1 Filed Oct. 1, 1958 INVENTOR. ljela ATTORNEY May 21, 1940. Y. SEKELLA GEAR CHANGING MECHANISM Filed Oct. 1, 1938 2 Sheets-Sheet 2 Patented May 21, 1940 UNITED STATES PATENT OFFICE GEAR CHANGING MECHANISM Application October 1,

8 Claims.

The present invention relates to gear changing mechanism for velocipedes and. more particularly to a snap-action operating means for controlling multi-speed gearing for bicycles.

Various forms of change speed gearing have been adapted for use in the propulsion of velocipedes such as bicycles, such devices usually making use of shiftable gears or shiftable keying means order to secure the various gear ratios. The successful operation of such devices entails shifting means for the gears or the keys which will make the desired shifts quickly and smoothly and with provisions for yielding elastically if the shifting action is momentarily impeded.

It is an object of the present invention to provide a novel shifting device for bicycle gearing which is efficient and reliable in operation while being simple and economical in construction.

It is another object to provide such a device which is arranged to shift a two-speed gear to either of its operating positions.

It is another'object to provide such a device which incorporates a yielding means serving to effect the shift quickly and gently and thereafter to maintain the parts in shifted position.

It is a further object to provide such a device which is mounted within the frame of. the vehicle so as not to project therefrom.

It is another object to provide such a device which is small and compact and performs its functions with short arcuate travel of the moving parts.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a sectional view of a two-speed bicycle gear embodying a preferred form of. the invention, the section being taken substantially on the line l-l of Fig. 2;

Fig. 2 is aplan view of the same partially broken away;

Fig. 3 is a vertical substantially mid-sectional View of a conventional bicycle brake embodying the present invention, the elements of the bicycle frame being omitted for the sake of clarity; and

Fig. 4 is a sectional View taken substantially on the line 4-4 of Fig. 3, showing an alternative arrangement of. anchor plate and torque arm.

In Figs. 1 and 2 of the drawings there is illustrated a portion i of the rear forks of a bicycle frame in which is rigidly mounted as by means of a nut 2 an axle member 3. A wheel hub 4 1938, Serial No. 232,811

(Fig. 3) is journalled by means of bearings 5, B and T on the axle 3 and is arranged to be actuated by' a sprocket 8 by means of two-speed planetary gearing. As here illustrated, the gearing comprises an orbit gear 9 formed in the sprocket 8, a plurality of planet pinions ll journalled on a planet carrier I2, and a sun gear l3 journalled on an adjustable bearing member l4 and meshing with the planets l l.

Means are provided for alternatively locking the sun gear !3 to the planet carrier l2 or to an anchor member l5 in the form of swinging key members I6 pivotally mounted on a carrier ll fixed to the sun gear l3 and having furcations adapted to alternatively engage recesses I8 in the planet carrier or recesses 19 in the anchor member lb.

The anchor member I5 has fixed thereto or formed integrally therewith a plate 21 (Figs. 1 and 2) arranged to extend forwardly from the axle 3 and to be rigidly attached to the fork l of the frame by suitable means such as a clampin'g member 22.

Means are provided for shifting the swinging keys 16 comprising a ring 23 extending between the furcations of the keys l6 and having peripheral lugs 24 extending radially through cam slots 25 (Fig. 3) in the anchor member l5 and into longitudinal grooves 28 in a shifting member 21 journalled on the anchor member l5. Oscillation of the shifting member 2? thus causes the ring 23 to move longitudinally and thereby swing the keys l6 from one operative position to the other.

According to the present invention, means are provided for moving the shifting member 21 from one operative position to the other by a yielding snap-action device which causes the shift to be made easily and quickly and without undue strain on the parts or lost motion in the transmission. As illustrated in Figs. 1, 2 and 3, this shifting means comprises a lever 28 pivoted at 29 on the anchor plate 2! and arranged to be manually operated by any suitable means such as a Bowden mechanism 3| through an arc of travel conveniently limited by abutment surfaces 32 and 33 of the anchor clamp 22. A link 34 is pivoted at 35 to the anchor plate 2i at a point radially outward from the pivot 29 of lever 28, and is provided with a sliding pivotal connection with an arm 36 fixed as indicated at 3'! to the shifting member 27. The sliding pivotal connection here illustrated comprises a pin 38 in the free end of link 34 which traverses a slot 39 in the arm 36. A

spring 4| is connected at one end to the pin 38 and at its other end to a pin 42 adjacent the free end of. the lever 28.

The abutments 32 and 33 are arranged to confine the travel of the lever 28 to an are which is bisected by a line radial to the bicycle hub and its associated parts, passing through the pivotal point 29 of the lever. The pivot 35 of link 34 is in the same radial plane as the pivot '29, and the length of the slot 39 in arm 36 issuch as to cause the link 34 to' limit the rotary movement of the shifting member 2'! to an arc of substantially less angular extent than the scope of movement of the lever 28.

It will thus be seen that with the parts in the operative position illustrated in Fig. 1, tension of the spring 4| yieldingly maintains theshifting member 2! in its clockwise rotated position with a force that is greatly augmented by the effect of the link 34 which, by reason of its angularity, firmly maintains the shifting member in this po sition. When the lever 28 is moved .down against the abutment 33 by the Bowden mechanism 3i, however, the spring 4! acts on both the shifting member 2! and link 3'4 to cause the shifting memher to rotate counterclockwise to a position similarly defined by the engagement of the pivot 38 in the end of the slot 39, in which position the shifting member 2'! is firmly maintained by the cooperation of the link 34 in an identical manner.

In the operation of the device, when the parts are in the positionsillustrated in Figs. 1, 2 and 3, the shifting member 27 is so positioned that the ring 23 maintains the key members 85 in engagement with the recesses l 9 in the anchor member. The sun gear I3 is thus prevented from rotation, and the planet carrier i2 is rotated by the sprocket 8 at reduced speed. When the lever 28 is swung to its lower position, the spring M is placed under increased tension androtated about the pivot 38 until it passes through the dead center position and causes the shifting member 27 to be quickly rotated to its opposite position. This rotation causes the ring 23 to move over to its high speed position, thus disengaging the keys Hi from the recesses IS in the anchor member and causing them to engage with the recesses la in the planet carrier. Since the keys l6 are actuated by the tension of spring 4 I, they are snapped vinto full engagement with the recesses l8 immediately upon alignment therewith. The sun gear is thus locked to the planet carrier so that the gearing rotates as a unit and the planet carrier is locked to the driving sprocket B.

It will be understood that the number of keys l6 and recesses l8 and Hi may be varied as deemed desirable. In the structure as illustrated there are three keys I6, three recesses l8, and six recesses l9, which arrangement has been found satisfactory in respect to mechanical strength and limitation of lost motion.

Since the transmission of rotation and braking force from the planet carrier to the wheel hub forms no part of the present invention, it is believed to be unnecessary to describe the same further than to state that these fuctions are accomplished in the manner described in the patent to Morrow 906,149.

In Fig. 4 of the drawings there is illustrated an embodiment of the invention in which the anchor plate 5! is arranged to extend rearwardly and above the fork of the bicycle frame, and is provided with a torque arm 52 extending beneath the fork and attached thereto by means of a clamp The shifting mechanism is the same as in the embodiment previously described, the elements thereof being similarly numbered, but the operating lever 28 is in this case actuated by a manually operable rod 53, and its arc of movement is limited by abutments 54 and 55 formed integrally as shoulders on the anchor plate 5|.

The operation of the shifting mechanism and the gearing in this embodiment of the invention is the same as that previously described.

Although but two embodiments of the invention have been shown and described in detail, it will be understood that other embodiments are possible and Various changes may be made in the dimensions and arrangements of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In a change speed gear for velocipedes and the like, shifting means including a rotatably mounted shifting member, a fixed anchor member, a lever pivoted to the anchor member, a link pivoted to the anchor member at a point radially outwardfrom the lever pivot in respect to the axis of the shifting member, a spring connected at its ends adjacent the free ends of the lever and link, and an operative connection between the free end of the link and the shifting member.

, 2. In a change speed gear for velocipedes and the like, shifting means including a rotatably mounted shifting member, a fixed anchor member, a lever pivoted to the anchor member, a link pivoted to the anchor member at a point radially outward from the lever pivot in respect to the axis of the shifting member, a spring connected at it ends. adiacent the free ends of the lever and link, a sliding pivotal connection between the free end of the link and the shifting member, means for limiting the rotary motion of the shifting member to an arc bisected by the radius passing through said fixed pivots, and manually operable means for swinging the lever.

3. Snap-action operating mechanism for a gear shift including a rotatable shifting member, an anchor member, a link and a lever pivoted at one end thereof to the anchor member in overlapping relation, a spring connected at its ends adjacent the free ends of the link and lever, and a lost motion pivotal connection between. the free end of the link and the shifting member.

4. Snap-action operating mechanism for a gear shift including a rotatable shifting member, an anchor member, a link and a manually operable lever pivoted at one end thereof to the anchor member in overlapping relation, a spring connected at its ends adjacent the free ends of the link and lever, and a pivotal connection between the free end of the link and the shifting member having freedom for limited relative sliding motion, said anchor member having means for limiting the arcuate movement of the lever.

5. Gear shifting mechanism for velocipedes including a rotatable shifting member, an anchor plate adapted to be fixed to the frame of the vehicle, a manually operable lever and a link pivoted at one end thereof to the anchor plate in radially overlapping relation in respect to the axisof the shifting member, a spring connected at its ends adjacent the free ends of the link and'lever, and

.a limited lost motion pivotal connection between the free end of the link and the shifting member, said anchor plate having shoulders limiting the swinging movement of the lever to an arc bisected by the line passing through thepivotal points of the link and lever.

6. In a two-speed gear for velocipedes or the like, an anchor plate, a shifting member mounted for rotary movement adjacent thereto, an actuat ing lever pivoted on said anchor plate, a spring connected at its ends to the shifting member and actuating lever, and means for so limiting the arcuate movement of the shifting member as to confine the point of connection of the spring thereto to movement through an arc bisected by a radius of the shifting member passing through the point of attachment of the actuating lever and of substantially less angular extent than the scope of movement of the actuating lever.

7. In a two-speed gear for velocipedes or the like, an anchor plate, a shifting member mounted for rotary movement adjacent thereto, an actuating lever pivoted on said anchor plate, a spring connected at its ends to the shifting member and actuating lever, means for so limiting the arcuate movement of the shifting member as to confine the point of connection of the spring thereto to movement through an arc bisected by a radius of the shifting member passing through the point of attachment of the actuating lever, and means for limiting the swinging movement of the actuating lever to an arc bisected by the same radius and of a substantially greater angular extent than the arc of movement of the shifting member.

8. In combination, a two-speed gear drive for velocipedes including an axle, a hub journalled thereon, a driving sprocket, means including change speed gearing connecting the sprocket and hub, an anchor member rigidly mounted on the axle, a shifting member for the gearing rotatably mounted on the axle adjacent the anchor member, and manually operable means for moving the shifting member including a link and a lever pivoted at one end thereof on'the anchor member in overlapping relation, a spring pivoted at its ends adjacent the free ends of the link and lever, and a pivotal connection between the free end of the link and the shifting member having freedom for limited; relative sliding motion.

YOUSTON SEKELLA. 

